From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Design of the 'Myth' exhaust system, contrasting theoretical mathematical solutions with practical workshop adjustments.
| Identifier | ExFiles\Box 159\5\ scan0080 | |
| Date | 28th October 1940 | |
| Ev.{Ivan Evernden - coachwork} from Rm.{William Robotham - Chief Engineer} c.c. Rm{William Robotham - Chief Engineer}/HH. c.c. Rba/Wym.{G. Harold Whyman - Experimental Manager} [Handwritten: Memos to Shop 1373] re MYTH EXHAUST SYSTEM. We have read your Ev.{Ivan Evernden - coachwork}5/JH.24.10.40. on this subject. Last time we were in America we were shown, in great confidence, a treatise on the mathematical solution of exhaust system design. We stayed up very late at night finding out what it was all about. We came home full of enthusiasm and decided to revise our cut-and-dried methods of the past. We worked with Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} on the job, and after several months endeavour, came to the conclusion that the mathematical solution did not work. We asked Olley to check up and he replied that General Motors practice was to calculate the position and dimensions of the chambers for a silencer to four places of decimals, and that the man in the Shop then adjusted the system when it had been made, with a hack-saw and foot-rule. I think, in dealing with the Myth exhaust system, we should accept that, for a 10 h.p. engine, the Vauxhall silencer is satisfactory, and whatever we make will be about that size. With regard to the thumper, we have a 100% silencer for this on our 8-cylinder cars with twin exhaust systems. One of these systems can be taken as a model where two expansion boxes are to be used. If you can get such a system in your frame we can silence any 4-cylinder engine. Rm.{William Robotham - Chief Engineer} | ||